Cranes are used in many different applications. For example, on construction sites, cranes are used to move large and/or heavy objects from one location to another. One important objective when operating a crane is to avoid collisions with other cranes and/or objects on the site, since collisions can be very hazardous and expensive.
To avoid collisions, a crane is operated manually by a human operator located inside a cab of the crane. Some times, the human operator can not see the load being moved and relies on directions from ground spotters that have visual contact with the load to operate the crane.
In addition to directions provided by ground spotters, locations of various components of the crane are provided to the crane operator to help prevent collisions. Typically, mechanical sensors are used to extrapolate a position of a component based on mechanical relationships between various components of the crane. For example, the height of an object being lifted can be determined based on the length of cable paid out from the crane.
One problem with this approach is that it is possible for the mechanical sensors to provide inaccurate information. In the example above, a mechanical sensor may not take into account the stretch of the cable and thus the height information provided to the operator could be inaccurate. In addition, since the mechanical sensors rely on physical relationships between various components, deflection of the components due to wind or other factors can lead to inaccurate readings from the mechanical sensors.
Inaccurate location information of crane components can lead to problems such as collisions with other objects and/or crane failures. The result of crane collisions and/or failures can be deadly and financially costly.